000 AXPZ20 KNHC 301539 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Fri Oct 30 2020 Tropical Weather Discussion for the eastern Pacific Ocean from the Equator to 32N, east of 140W. The following information is based on satellite imagery, weather observations, radar, and meteorological analysis. Based on 1200 UTC surface analysis and satellite imagery through 1500 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: High pressure and cooler, denser air follow a cold front that has moved across the Gulf of Mexico. Earlier scatterometer data and regional observations suggest this cooler air has punched through the Tehuantepec isthmus and gale are likely ongoing into the Gulf of Tehuantepec. These winds are likely peaking at 45 kt this morning. Winds will diminish slightly to minimal gale this afternoon through Sat night. A reinforcing cold front is expected to move into the southwest Gulf by early Sun allowing for gale force winds to increase back to near 45 kt Sun night through early next week. Short period northerly swell will mix with longer period southerly swell to support seas in excess of 8 ft well downstream of the Gulf of Tehuantepec. Peak seas during the gale winds are around 14 ft today. Peak seas are forecast to build to near 20 ft by early next week with the reinforcing front and winds and an expansion in coverage of such. Please refer to the latest High Seas Forecast issued by the National Hurricane Center at website https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for further details. ...TROPICAL WAVES... A tropical wave axis is along 87W from N of 02N to near the Gulf of Fonseca, moving W at around 10 kt. Associated convection is described below. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 10N86W to low pressure near 10N89W to 08N 95W to 13N115W to 10N130W to 10N140W. Scattered moderate and isolated strong convection is noted from 06N to 10N between 88W and 93W, from 08N to 16.5N between 96W and 102W, from 10N to 13.5N between 115W and 124W, and from 06N to 10N between 128W and 134W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please refer to the special features section for details on the Gulf of Tehuantepec Gale Warning. High pressure west of Baja California is supporting gentle to moderate northerly breezes across the Mexican offshore waters off Baja California and the Gulf of California. Seas are mostly 2 to 4 ft in both the open waters and in the Gulf of California. Seas will build to 4 to 6 ft in the waters of Baja California by early next week. Elsewhere, little change is expected through the next several days. Farther south, moderate northerly winds are funneling off Cabo Corrientes, and seas are likely 4 to 6 ft off the Jalisco and Colima coasts in mostly southerly swell. Gentle winds and 3 to 5 ft elsewhere off southern Mexico outside of the Gulf of Tehuantepec. Seas will start building tonight as increased southerly swell moves into the area, reaching up to 9 ft off Michoacan and Guerrero by late Sat, then subsiding into early next week. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR... Moderate south to southwest winds will prevail south of the monsoon trough through Sun, with isolated areas of fresh winds ahead of a tropical wave. Seas are expected to increase offshore of Guatemala and El Salvador through Sat night due to gale force winds in the Gulf of Tehuantepec pushing northerly waves into the area. Larger seas are expected early next week across this same area due to greater coverage and strength of the Tehuantepec gap winds NW of the area. Elsewhere seas are mainly 4 to 7 ft in mainly long period southerly swell. Seas will build slightly south and east of the Galapagos Islands late this weekend into early next week due to reinforcing southerly swell. Moderate offshore gap winds are expected across the Papagayo region through Sun before turning onshore Mon through Tue. REMAINDER OF THE AREA... A trough extends from 29N130W to 26N132W to 19N119W, disrupting a broad ridge of high pressure across the waters north of 20N. Another trough extends from 19N117W to 14N111W. The troughs are forecast to drift W through the weekend. The gradient between the ridge and lower pressures associated with the monsoon trough will support moderate to fresh NE trade winds over an area roughly from the monsoon trough to 20N, west of 115W, for the next several days. Seas are 5 to 8 ft across this region, in a mix of swell and easterly wind waves. Little change is expected through the weekend. A complex low pressure system north of the Hawaiian Islands is forecast to move NE through the weekend. A weak trailing cold front may slip southeast of 30N140W early next week with winds remaining 20 kt or less. Associated seas will build to 8 to 9 ft behind this boundary. South of the monsoon trough, moderate to fresh S to SW winds prevail between 100W and 140W, where seas are 5 to 8 ft. Minor fluctuations in winds and seas are expected across this area through the weekend. Looking ahead, computer models suggest that a tropical wave moving offshore of SW Mexico Sun and Mon could spawn a low pressure center forming west of the offshore waters in the vicinity of 10N110W by Mon morning, and move WNW through mid week. $$ Lewitsky